package utils;

import com.mysql.cj.jdbc.MysqlDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {
    // 数据源
    private static DataSource dataSource = null;
    // 数据库连接串
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/mysql_practice?characterEncoding=utf8&allowPublicKeyRetrieval=true&useSSL=false";
    // 用户名
    private static final String USER = "root";
    // 密码
    private static final String PASSWORD = "Langwang0823*";

    // 当类加载到JVM时，执行数据源的初始化
    static {
        MysqlDataSource mysqlDataSource = new MysqlDataSource();
        mysqlDataSource.setURL(URL);
        mysqlDataSource.setUser(USER);
        mysqlDataSource.setPassword(PASSWORD);
        dataSource = mysqlDataSource;
    }

    // 获取数据库连接
    public static Connection getConnection() throws SQLException{
        return dataSource.getConnection();
    }

    // 构造方法私有化，防止new这个对象
    private DBUtil(){}

    // 释放资源，关闭连接
    public static void close(ResultSet resultSet, Statement statement, Connection connection){
        if(resultSet != null){
            try{
                resultSet.close();
            }catch(SQLException e){
                e.printStackTrace();
            }
        }
        if(statement != null){
            try{
                statement.close();
            }catch(SQLException e){
                e.printStackTrace();
            }
        }
        if(connection != null){
            try{
                connection.close();
            }catch(SQLException e){
                e.printStackTrace();
            }
        }
    }


}
